1. Field of the Invention
This invention relates to a sheet handling apparatus which receives series of recording sheets discharged from an image recording apparatus such as a copier, a printer or the like on a handling tray in a stack and carries out handling on the stack of sheets, e.g., lining up the edges of the sheets.
2. Description of the Related Art
There has been known a sheet handling apparatus which, for instance, stacks a series of recording sheets discharged from a copier, a printer or the like on a handling tray, lines up the edges of the sheets and staples the sheets together.
If a recording sheet of the next series is fed on a stack of a series of recording sheets while the stack of sheets is handled, a desired handling cannot be carried out on the stack and there is fear that the recording sheet of the next series is carried out from the handling tray together with the stack of the recording sheets. On the other hand, when the sheet handling apparatus is arranged to receive recording sheets of the next series after handling of the recording sheets of the preceding series, the working efficiency of the sheet handling apparatus deteriorates.
Thus it has been proposed to provide a retractable auxiliary tray between the handling tray and a discharge roller of the image recording apparatus and to separate recording sheets of the next series from the stack of recording sheets of the preceding series on the handling tray by temporarily supporting the recording sheets of the next series on the auxiliary tray until handling of the recording sheets of the preceding series is completed. See, for instance, Japanese Unexamined Patent Publication Nos. 63(1988)-154578 and 63(1988)-180673.
It is desirable that such an auxiliary tray be as small as possible from the viewpoint of reducing the size of the overall apparatus. However when the auxiliary tray is small, it becomes difficult to surely support the recording sheets. Accordingly the auxiliary tray disclosed in the above identified Japanese patent publications comprises a stationary part and a movable part and only the movable part is projected to support the recording sheet together with the stationary part. Accordingly the structure of the auxiliary tray is complicated and the overall size of the auxiliary tray is large, which is not desirable from the viewpoint of reducing the size of the overall apparatus.
By the way, since a plurality of recording sheets are stacked on the handling tray and it is very difficult to move up and down the handling tray due to the limited space in the apparatus, the handling tray must be positioned below the discharge port, through which the recording sheet is discharged to the handling tray, at a substantial distance therefrom, which gives rise to the following problem. That is, if a recording sheet is discharged from the discharge port directly onto the handling tray, the leading edge of the recording sheet is hung down from the discharge port and abuts against the upper surface of the handling tray or the surface of the recording sheet thereon, which can cause the recording sheet to be buckled or turned over. Such problems is more apt to arise when there is no recording sheet on the handling tray due to a recess and/or a slot formed on the handling tray for permitting movement of various member for handling the sheets. A buckled recording sheet is apt to cause jamming.